Encoder



Feb. 2, 1965 A. s. ROBINSON ENCODER 3 Sheets-Sheet 1 Original FiledApril 15, 1959 lOJk mjm INVENTOR. ARTHUR 5. ROB/NSON HTTOR VEY Feb. 2,1965 A. s. ROBINSON 3,168,643

ENCODER Original Filed April 15, 1959 3 Sheets-Sheet 3 FIG. 5

INVENTOR ARTHUR S. ROBINSON 3,168,643 ENCUDER Arthur S. Robinson, outhHuntington, N.Y., assignor to The Bendix Qorporation, a corporation ofDelaware firiginal appiicatiou Apr. 15, 1959, Ser. No. 8%,625. Dividedand this application Jan. 2, i964, Ser. No.

20 Claims. (Cl. 235--61.6)

which provides a substantial number of arbitrary functions of a variableon a single unit.

Another object is to provide an encoder in which the functions are trulyarbitrary and may include steep slopes and discontinuities.

Another object of the invention is to provide an encoder which operatesindependently of the encoder drive motor speed. I

Another object is to provide an encoder which is simple in design andmay readily be mass produced.

Another object is to provide an encoder in which intelligence may beencoded on a cylinder or disc or any other suitable device.

The invention contemplates a function encoder. comprising a member, suchas a cylinder or disc, having intelligence thereon corresponding to apreselected fur1ction which varies in value in accordance with acondition,

pick-up means for scanning the member and providing signals, and meansfor controlling the pick-up means in accordance with the condition sothat thesignals from to the preselected function. a series of pulseswhich may be applied to a counter so that the digital output of thecounter corresponds to the condition according to the preselectedfunction.

.The foregoing and other objects and advantages of the invention willappear more fully hereinafter .from a con-- sideration of the detaileddescription which follows, taken together with the accompanying drawingswherein several embodiments of the invention are illustrated by way ofexample. It is to be expressly understood, however, that the drawingsare for illustration purposes only and are not to be construed asdefinnig the limits of the invention.

Inthe drawings: 7

FIGURE 1 is a schematic diagram of a novel encoder constructed accordingto the invention.

FIGURE 2 is a schematic diagram similar to FIGURE 1 showing asecond'embodiment of the invention.

FIGURES 3 and 4 are schematic diagrams of novel encoders having severalfunctions on a single cylinder.

FIGURE 5 is a-schematic diagram showing another embodiment of theinvention in which the function is stored on a disc instead of acylinder.

In FIGURE 1, the novel encoder shown therein and constructed accordingto the invention comprises an opaque cylinder ll having intelligencethereon in the form of a short transparent reference line 3 and a curvedtransparent reference or function line 5 shaped to provide a graph of adesiredarbitrary preselected function of a variable condition. Theinterior of the drum may be United States Patent the pick-up meanscorrespond to the condition according The signals may comprise lightedin any suitable manner and in the present embodiment an elongated fixedlight source 7 is positioned within cylinder l. The cylinder is rotatedat relatively high speed by a motor 9 through a shaft 11.

A photo-electric pick-up 113 is moved in any suitable manner lengthwiseof the cylinder and parallel to the cylinder axis and perpendicular tothe direction of rotation of the cylinder in accordance with the:variable condition. Pick-up 13 may comprise a photocell 17 enclosedwithin a shield 19 having a small aperture 21 therein adjacent thecylinder to transmit light from the light source '7 to the photocellwhen function line 5 is coincident with the aperture. .In the embodimentshown, pick-up 13 is moved parallel to the cylinder axis throughsuitable linkage 25 by an aneroid 23 responsive to pressure.

A fixed picloup 27 similar to pick-up 13 is positioned adjacent cylinder1 and is aligned lengthwise of the cylinder with reference lined. Ascylinder ll rotates, a first reference pulse referred to hereinafter asa reference pulse is produced by pick-up 27 each time reference line 3passes the pick-up and a second reference pulse, hereinafter referred toas a function pulse is produced by pick-up 13 each time function. line 5passes the pick-up. One reference pulse and one function pulse areproduced with each revolution of the cylinder and the spacing of thepulses is determined by the circumferential distance between thereference line and function line at the place being scanned by pick-up13.

The encoder may be made independent of motor speed by providing a fixedphotoelectric pick-up 31, similar to pick-up 1.3, for scanning a seriesof transparent increment lines 29 equally spaced about the circumferenceof cylinder 11 so that a pulse is produced each time an increment line'29 passes pick-up 31. With this arrangement, the accuracy of the encoderdoes not depend on uniform speed of rotation of motor 9 because thedistance between reference line 3 and function line 5 is measured byincrement lines 29 and not by a time interval.

The pulses from pick-ups 13,27 and 31 are amplified to a flip-flopcircuit 39 which may be of the kind shown at page 47'of ArithmeticOperation. in Digital Computers by R. K. Richards and published by D.Van

Nostrand (30., Inc. The reference and function pulses set and re-set theflip-flop reference circuit so that a direct current voltage isalternately provided at outputs 3% and 39b. The flip-flop circuit actsas a switching arrangement and provides a DC. output at 39Wh611 reset bya reference pulse and provides no output at 39a when set by a functionpulse. The flip-flop circuit also provides a DC. output at 3% when setby afunction pulse and no output at 3% when reset by a reference pulse.Thus, the flip-flop circuit provides a DC. output at 3% in the intervalbetween the reference pulse and the function pulse and no output at 39ain the interval between the function pulse and the reference pulse.Also, the flip-flop circuit provides no DC. output at 3% in the intervalbetween the reference pulse and the function pulse and a DID. output at3% in the interval between the function pulse and the reference pulse;

The DC. output 39a of .iiip-fiop circuit 39 together with the amplifiedincrement pulses from pick-up 31 are applied to an and gate 41 which maybe of the kind shown at page 74 of Arithmetic Operation in DigitalComputers by R. K. Richards and published by D. Van Nostrand Co., Inc.and which passes the increment pulses only when the gate is energized bythe direct current output saafrom flip-flop 39. During each revolutionof cylinder 1, the and gate passes the increment pulses Patented Feb. 2,1965 in the interval between the reference pulse and the function pulseand blocks the increment pulses in the interval between the functionpulse and the reference pulse.

The reference pulses from pick-up 2') are applied to the reset line of adigital counter 43 and each pulse resets the counter. The digitalcounter may be of the kind shown at page 194 of Arithmetic Operation inDigital Computers by R. K. Richards and published by D. Van NostrandCo., Inc. The gated increment pulses from and gate 41 are applied to thedigital counter 43 during the interval between the reference pulse andthe function pulse and provide a parallel binary number in the counter.The increment pulses are stopped by and gate .1 during the intervalbetween the function pulse and the reference pulse and do not reach thecounter during this interval. During this interval also the DC. output3% of flip-flop 39 transfers the unchanging parallel binary number inthe digital counter corresponding to the desired digital reading to thecontrolled or computer circuit using this information by means ofconnection 3% and designated T .0 (transfer command).

With the arrangement described, the mechanical displacement of pick-up13 is converted at counter 43 to a digital output which is an arbitraryfunction of the displacement.

The novel encoder shown in FIG. 2 is similar to the encoder shown inFIG. 1 except that reference line 293 extends substantially the lengthof cylinder Z'l l and pickup 213 scans both function line 2% andreference line 2%. This arrangement facilitates laying out the functionand reference lines. In this embodiment, pick-up 213 comprises anelongated light sensitive surface 217 and a shield 219 adjacent theretoand movable parallel to the cylinder axis. An ordinary bulb 2d? may beused as the light source and the bulb is mounted within cylinder Bill ona bracket 2% fixed to shield 219 and extending into an open end ofcylinder Ztll. Shield 219 has a small aperture 221 therein opposite bulb2t)? which permits light from the interior of cylinder Ztlll to fallupon light sensitive surface 217 each time reference line 2&3 andfunction line 2% pass the aperture to provide alternate referenceandfunction pulses. Increment lines 229 and pick-up 231 are providedsimilar to increment 7 lines 29 and pick-up 31in FIG. 1.

With this arrangement, the reference pulses and the function pulses areidentified by setting a fiip'dop circult 238 With synchronizing pulsesfrom a pulse former 21% connected to the same excitation source used tooperate synchronous motor sea which drives cylinder Zill. Onesynchronizing pulse occurs just before the reference pulse for eachcylinder revolution and provides only an approximate reference, sincethe motor may vary in phase and depart from exact synchronisn with thefrequency of the excitation source.

The reference and function pulses from pick-up 213 are amplified byamplifier 233 and the increment pulses from picloup 231 are amplified byamplifier 237. The amplified reference and function pulses are appliedto and gates 24% and 2 .2 controlled by outputs 238a. and 2381) offlip-flop 23%, respectively. And gate 242 is open and passes referencepulses only when a direct current voltage is present at output 238i) offlipflop circuit 238 and and gate 240 is open and passes function pulsesonly when a direct current voltage is resent at output 2138a offlip-flop circuit 238.

The synchronizing pulses from pulse former 210 set flip-flop circuit 238so that a direct currentvoltage appears at output 238]; and no voltageis present at output 2355a. The reference pulses passed by and gate 242reset flip-flop circuit 238 so that no direct current output is presentat 2385 and a direct current output appears at 238a.

With this arrangement the function pulses and reference pulses areseparated and operate flipflop circuit 239 to open and close and gate241 so that increment pulses from amplifier 237 are passed to counterare encoded on a cylinder Sill and the function lines are scanned by asingle pick-up 313 which provides a function pulse for each functionline. The cylinder has a reference line M3 and linearly spaced incrementlines 329 thereon scanned by pick-ups 327 and 331, respectively, whichprovide reference and increment pulses. The function pulses from pick-up313, the reference pulses from pick-up .327 and the increment pulsesfrom pick-up 331 are amplified by amplifiers 353, 335, and 3337,respectively.

Since a function pulse occurs for each function line with eachrevolution of the cylinder, suitable means are provided to identify thedesired function pulse and reject the remaining function pulses uponeach revolution of cylinder The amplified function pulses from piclo up313 and amplifier 333 are applied to and gate 302 which is controlled bydigital counter 3&4 to pass only the desired function pulse and blockthe other pulses.

1 code pattern applied to control lines 306a and 3%];

of diode matrix 3% is transferred in parallel through the diode matrixto counter 3% by each reference pulse from pick-up 327 applied to thematrix at control lines 3860 to preset the counter upon each revolutionof cylinder 391 so that a fixed number of function pulses are requiredto set the counter to 0. And gate 3&2 is energized by counter so thatthe gate opens only when the counter reading is 0.

If, for example, the first function line 395a. is selected, thereference pulse presets counter sea to 0 under control of control linesfitlda and Sfitfb. Gate Zilll then passes only the first function pulse.The function pulses also are applied via delay line 3% to counter 304,changing the counter reading to 1 thus closing gate 3 312.

If the second function pulse is to be selected, counter see is preset bythe reference pulse to a reading corre-' sponding to the maximum countercapacity. The first function pulse to appear after the reference pulseis blocked by gate 3&2 but is applied via delay line 3% to counter Sitladvancing the counter reading to 0. The second function pulse, which isthe desired pulse, then passes directly through gate SM and, via delayline 36%; advances counter Eludto l, thus again closing gate 302.

Any desired function on cylinder 361 can be selected in this manner byappropriately presetting counter 394 by the reference pulse with asuitable code pattern on control lines Edda and iitldb of diode matrix3%.

The selected function pulse from and gate and amplified referencepulsefrom pick-up 327 and amplifier 335 are applied to flip-flop circuit 339and the direct current output of fliplop circuit 339 controls ant gate341 'to pass to digital counter 343 increment pulses from'pick-up 331 inthe interval between the reference pulse and the selected function pulseand to block increment pulses in the interval between the selectedfunction pulse and reference pulse for each revolution of cylinder 3M,similarly to FIG. 1. i

The encoder shown in FIG. 4 is similar to that shown in FIG. 3 exceptthat in FIG. 4 function lines 465a, ulfil; and itific of differentcolors are used with correspondingly colored filters 419a, 43 .912, and41% on pickups 413a, 4131), and 4130 to facilitate identifying thedesired function pulses. With this arrangement, the function pulse foreach function line appears on a separate pick-up.

Reference line dill: and linearly spaced increment lines are scanned byfixed pick-ups 427 and 431, respectively. Function pulses from pick-ups4125a, 4 33b, and 4130 are amplified by amplifiers i -33a, 4333b, and4330, respectively. Also, reference and increment pulses from I and gateduring each cylinder revolution so that only one function pulse willappear at the output of or gate 436 connected to the and gates. The orgate may be of the .kind shown at page 74 of Arithmetic Operation inDigital Computers by R. K. Richards and published by D. Van NostrandCo., Inc. Selection of the desired function is therefore simplyaccomplished by opening the appropriate and gate. The selected functionpulse is applied to flip-flop circuit 439 and the desired reading ofincrement pulses is obtained in digital counter 443 in a manneridentical to FIG. 1.

The arrangement in FIG. stores the intelligence on a disc 601 instead ofon cylinders as in the embodiments shown in FIGS. 1 thru 4. Thearrangement shown in FIG. 5 stores a plurality of arbitrary functions asin FIG. 3. The intelligence comprises a graph arranged circularly aboutthe center of the disc in the form of function lines 6li5a, dtidb, and6050, equally spaced increment lines 629 and a reference line 693. Aradially movable pick-up 613 scans the function lines and fixed pick-ups631 and 627 scan the increment lines and reference line, respectively.The function pulses from pick-up 613, the increment pulses from pick-up631 and the reference 7 pulsesfrom pick-up 627 are amplified and controla digital counter in the same manner as in FIG. 3.

The encoder described herein and constructed according to the inventionconverts mechanical displacements to digital numbers according to anyarbitrary predetermined function of the displacement and the encoder isaccurate, compact, light in weight and has a high degree of resolution.The encoder may be used to provide a substantial number of arbitraryfunctions of a variable on a single unit and the functions are trulyarbitrary and may include steep slopes and discontinuities. The encoderoperates independently of the encoder drive motor speed and is simple indesign and may readily be mass produced.

Instead of using photoelectric pick-ups responsive to illuminatedtransparent function lines as described herein, capacitive or inductivesensing may be used by inscribing the reference and function lines. asconducting surfaces or as magnetic material and using capacitive orinductive pick-ups to detect the passage of a line and providecorresponding pulses. I

While several embodiments of the invention have been illustrated anddescribed in detail, it is to be expressly understood that the inventionis not limited thereto.

Various changes may also be made in'the design and ar rangement of theparts without departing from the spirit and scope of he invention as thesame will now be ,understood by those skilled in the art. While in theem bodiments shown the cylinder or disc is rotated and the pick-up ismoved in response to a condition, in some instances it may be desirableto rotate the pick-up and move the cylinder or disc in response to thecondition or some other arrangement may be used for providing thedesired relative movement. Also, While the several embodiments have beendescribed for convenience as counting the increment pulses in theinterval between the reference and function pulses, it should beunderstood that in some instances it may be desirable to count theincrement pulses in the interval between the function and referencepulses in which case the function pulses would start a counting periodand the reference pulses would end the-counting period. t

6 What is claimed is: r 1. A function encoder comprising a member havingreference and function intelligence thereon, the function intelligencecomprising a graph varying in accordance with a condition according to apreselected function, pickup means for scanning the referenceandfunction intelligence and providing reference and function signals andincluding a part responsive to the condition to scan the graph inaccordance with the conditionto vary the interval between the signals inaccordance With the condition, and means for measuring the intervalbetween the signals.

2. A function encoder comprising a member having reference, increment,and function intelligence thereon,

the function intelligence comprising a graph varying in 1 accordancewith a condition according to a preselected function, pick-up means forscanning the reference and function intelligence and providing referenceand function signals and including a part responsive to the condition toscan the graph in accordance with the condition to vary the intervalbetween the signals in accordance with the condition, and pick-up meansfor scanning the increment intelligence to provide an output formeasuring the interval betweenthe signals.

3. A function encoder comprising a member having reference, increment,and function intelligence thereon, the function intelligence comprisinga graph varying in accordance with a condition according to apreselected function, pick-up means for scanning the reference andfunction intelligence and providing reference and function signals andincluding a part movable along the graph in response to the condition toscan the graph at a point corresponding to the condition to vary theintervalbetween the signals in accordance with the condition, and

pick-up means for scanning the incrementintelligence to provide anoutput for measuring the interval between the signals.

4. A function encoder comprising a member having reference, increment,and function intelligence thereon, the function intelligence comprisinga graph varying in accordance with a condition according to apreselected function, pick-up means for scanning the reference andfunction intelligence and providing reference and function signals andincluding a part movable along the graph perpendicularly to thedirection of rotation of the member in response to the condition to scanthe graph at a pointcorresponding to the condition to vary the intervalbetween the signalsin accordance with the condition, and

pick-up means for scanning the increment intelligence to provideanoutput for measuring the interval between the signals. i i Y r 5. Afunction encoder comprising a member having reference, increment, andfunction intelligencethereon, the function intelligence comprising agraph varying in accordance with a condition according to a preselectedfunction, pick-up means for scanning the reference and functionintelligence and providing reference and function signals and includinga part responsive to the condition to scan the graph at a pointcorrcspondingto the condition to vary the interval between the signalsin accordance with the condition, pick-up means for scanning theincrement intelligence and providing pulses, counting means connected tothe pick-up means providing increment pulses, and means connected to thepick-up means providing reference and function signals and controllingthe counting means to respond to increment pulses in the intervalbetween the signals to provide an output corresponding to the conditionaccording to the preselected function.

6. A function encoder comprising a member having reference, increment,and function intelligence thereon, the function intelligence comprisingagraph varying in accordance With a condition according to :a preselectedfunction, pick-up means for scanning the reference and functionintelligence and providing reference and function signals and includinga part responsive. to thecondition to scan the graph at a point correspto the condition to vary the interval between the signals in accordancewith the condition, pick-up means for scanning the incrementintelligence and providing pulses in accordance with the intervalbetween the signals, and means connected to the pick-up means providingthe reference and function signals and theincrement pulses andresponsive to the increment pulses in the interval between the signalsand providing an output corresponding to the condition according to thepreselected function.

7. A function encoder comprising a having reference, increment, andfunction intelligence thereon, the function intelligence comprising agraph varying in accordance with a condition according to a preselectedfunction, pick-up means for scanning the reference and functionintelligence and providing reference and function signals, pick-up meansfor scanning the increment intelligence and providing pulses, meansproviding relative movement between the member and pick-up means, saidpick-up means scanning the function intelligence being responsive to thecondition to scan the graph at a point corresponding to the condition tovary the interval between the signals in accordance with the condition,and

means connected to the picloup means providing the reference andfunction signals and the increment pulses responsive to the incrementpulses in the interval between the signals and providing an outputcorresponding to the condition according to the preselected function.

.8. A function encoder comprising a member having a reference line andan elongated function line thereon, the latter varying in accordancewith a condition according to a preselected function, pick-up means forscanning the member and providing a pulse each time the reference lineand function line pass the pick-up means and having a part movablelengthwise of the function line in response to the condition to scan thefunction line at a point corresponding to the condition to vary theinterval between pulses in accordance with the condition, and means formeasuring the interval between the pulses.

9. A function encoder comprising a member having reference, increment,and function intelligence thereon,

. the function intelligence comprising a graph varying in accordancewith a condition according to a preselected function, pick-up means forscanning the reference and function intelligence and providing referenceand function signals and including a part movable lengthwise of thegraph in response to the condition to scan the graph at a pointcorresponding to the condition to vary the interval between the signalsin accordance with the condition, and pick-up means for scanning theincrement intelligence to provide an output for measuring the intervalbetween the signals.

it). A function encoder comprising a cylindrical member havingreference, increment, and function intelligence thereon, the functionintelligence comprising a on the member, a photoelectric pick-up forscanning the member and responsive to the reference line and providing apulse each time thereference line passes the pick-up, a photoelectricpick-up movable in response to the condition to scan the function lineat a point corresponding to the condition and providing a pulse eachtime the function line passes the pick-up, and means for measuring theinterval between the pulses.

12 A function encoder as described in claim ii in which the means formeasuring the interval between the pulses includes a series of equallyspaced increment lines on the member and a fixed photoelectric pick-upproviding a pulse each time an increment line passes the pick-up.

13. A function encoder as described in claim 12 which includes a counterand means connected to the pickups responsive to the reference andfunction lines for applying the increment pulses to the counter in theinterval between the reference and function pulses.

14. A function encoder comprising a member having reference andincrement intelligence and a plurality of function intelligence thereon,the latter varying in accordance with a condition according topreselected functions, picloup means for scanning the intelligence toprovide reference, increment and function pulses on coincidence of thepick-up means and the corresponding intelligence, means for controllingthe pick-up means scanningthe function intelligence in accordance withthe condition to vary the interval between the reference pulse and apreselected function pulse in accordance with the condition, a counterconnected to the pick-up means providing increment pulses, and meansconnected to the pick-up means providing reference and function pulsesfor applying the increment pulses to the counter in the interval betweenthe reference pulse and preselected function pulse.

15. A function encoder comprising a disc having increment intelligenceand a plurality of reference intelligence thereon, one referenceintelligence comprising a graph arranged circularly about the center ofthe disc and varying in accordance with a condition according to apreselected function, a motor for rotating the disc, pick-up means forscanning the intelligence to provide increment and first and secondreference pulses on coincidence of the pick-up j means and theintelligence, the pick-up means for prograph varying in accordance witha condition according to a preselected function, pick-up means forscanning the reference and function intelligence and providing referenceand function signals and including a part movable parallel to-thecylinder axis in response to the condition to scan the graph at a pointcorresponding to the condition to vary the interval between signals inaccordance with the condition, pick-up means'for scanning the incrementintelligence and providing pulses on coincidence of the pick-up meanswith the increment intelligence, a counter connected to the pick-upmeans providing increment pulses, and means connected to the pick-upmeans providing reference and function signals for applying theincrement pulses to the counter only in the interval between thesignals.

11.' A function encoder comprising a member having a reference line andan elongated function line thereon, the latter comprising a graphvarying in accordance with a condition according to a preselectedfunction, a motor rotating the member, a light source illuminating thelines viding the one reference pulse being movable parallel to theradius of the disc to vary the interval between the reference pulsesaccording to the preselected function, a counter connected to thepick-up means providing increment pulse and means connected to thepick-up means providing reference pulses for applying the incrementpulses to the counter only in the interval between the reference pulses.I

16. A function encoder comprising a member having a reference line and aplurality of function lines thereon,

the latter varying in accordance with a condition according topreselected functions, a motor rotating the member, a light sourceilluminating the lines on the member, a fixed photoelectric pick-upresponsive to the reference line and providing a pulse each time thereference line passes the pick-up, a photoelectric picloup movable inresponse to the condition and responsive to the function lines andproviding a pulse each time a function line passes the latter pick-up,and means for measuring the interval between pulses from the picloups,one of the pulses corresponding to a preselected function pulse.

17. A function encoderas described in claim 16 in which the movablephotoelectric pick-up includes a PlLl-r rality of photo cells eachresponsive to a different color and the function lines are ofcorresponding colors to facilitate preselection of the function pulses.

18. A function encoder as described in claim 16 in which the means formeasuring the interval between the pulses includes a series of equallyspaced increment lines on the member and a fixed photoelectric pick-upproviding a pulse each time an increment line passes the pick-up.

19. A function encoder as described in claim 18 which includes a counterand means connected to the pick-ups responsive to the reference andfunction lines for applying the increment pulses to the counter in theinterval between the pulses. V

20. A function encoder comprising a member having reference intelligenceand a plurality of function intelligence thereon, the latter varying inaccordance with a condition according to preselected functions, pick-upmeans for scanning the intelligence on the member and the pick-up meansscanning the function intelligence being controlled in accordance withthe condition, and means connected to the picleup means scanning thereference and function intelligence for providing an outputcorresponding to the relative displacement of the reference and apreselected function intelligence at the place the function intelligenceis being scanned by the associated pick-up means.

No references cited.

3. A FUNCTION ENCODER COMPRISING A MEMBER HAVING REFERENCE, INCREMENT,AND FUNCTION INTELLIGENCE THEREON, THE FUNCTION INTELLIGENCE COMPRISINGA GRAPH VARYING IN ACCORDANCE WITH A CONDITION ACCORDING TO APRESELECTED FUNCTION, PICK-UP MEANS FOR SCANNING THE REFERENCE ANDFUNCTION FUNCTION INTELLIGENCE AND PROVIDING REFERENCE AND FUNCTIONSIGNALS AND INCLUDING A PART MOVABLE ALONG THE GRAPH IN RESPONSE TO THECONDITION TO SCAN THE GRAPH AT A POINT CORRESPONDING TO THE CONDITION TOVARY THE INTERVAL BETWEEN THE SIGNALS IN ACCORDANCE WITH THE CONDITION,AND PICK-UP MEANS FOR SCANNING THE INCREMENT INTELLIGENCE TO PROVIDE ANOUTPUT FOR MEASURING THE INTERVAL BETWEEN THE SIGNALS.